feat(stdlib): Tiled P2 — collision normalisation into the Solids feed (#70)

Normalise three collision sources into the byte tilemap esys_move / Grid.* /
Path.* read, in the design's priority order (§3.5):

- per-tile <objectgroup> hitboxes (Tiled.tile_shapes) — the precise source;
- the solid/oneway/trigger bool property convention (Tiled.collision_kind);
- the designated collision layer — any non-zero GID solid (Tiled.project),
  the fallback source, applied automatically on load.

Tiled.collide drives collision from a visual layer's per-tile metadata alone
(a tile with no collision metadata stays passable). tmap_collision_kind
classifies a GID (0 none / 1 solid / 2 one-way / 3 trigger) from its metadata;
the projection adds the collision-layer fallback.

Proven by library/tiled_p2.ludic (14 assertions): kind classification for each
source, the property convention and collision-layer fallback producing an
identical Solids feed, a per-tile-<objectgroup> floor blocking an esys_move
mover, and A* over a loaded map matching the hand-authored baseline. x test:
93 passed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/backend/emit_call.ludic

@@ -622,8 +622,11 @@ function emit_ns_call(ns: pointer, meth: pointer, e: Node) -> Val {
     if (meth == "layer_name")  { bare = "tmap_layer_name";   push(labels, "map"); push(labels, "index") }
     if (meth == "draw")        { bare = "tmap_draw";         push(labels, "map"); push(labels, "camx"); push(labels, "camy") }
     if (meth == "project")     { bare = "tmap_project";      push(labels, "map"); push(labels, "layer") }
+    if (meth == "collide")     { bare = "tmap_collide";      push(labels, "map"); push(labels, "layer") }
+    if (meth == "collision_kind") { bare = "tmap_collision_kind"; push(labels, "map"); push(labels, "gid") }
     if (meth == "tree")        { bare = "tmap_tree";         push(labels, "map") }
     if (meth == "tile_prop")   { bare = "tmap_tile_prop";    push(labels, "map"); push(labels, "gid"); push(labels, "name") }
+    if (meth == "tile_shapes") { bare = "tmap_tile_has_shapes"; push(labels, "map"); push(labels, "gid") }
   }
   # #62: a package-provided namespace (declared with @Namespace(Foo)) that none
   # of the hardcoded core blocks matched — alias Foo.method to the bare function